Pilot Multilocus DNA-Barcoding Assessment of Four Morus alba L. Accessions from Mangystau, Kazakhstan, with Low-Coverage Oxford Nanopore Quality Control

Abstract

The reliable identification of cultivated and naturalised mulberries is complicated by morphological plasticity, the historical movement of the planting material, and partly discordant nuclear and plastid signals. We evaluated four field-identified Morus alba L. trees, one from each of four localities in Mangystau, Western Kazakhstan, using archived consensus sequences for ITS, matK, rbcL, and trnH-psbA, together with a low-coverage Oxford Nanopore Technologies (ONT) dataset. Because the design comprised one tree per locality (n = 4), analyses were restricted to accession-level descriptive comparisons, and no population-genetic, phylogeographic, or formal phylogenetic inference was attempted. Archived alignment summaries indicated mean pairwise distances of 0.13% for matK, 0.44% for ITS, 0.94% for rbcL, and 2.92% for trnH-psbA; these values are reported as retained dataset descriptors rather than estimates of population diversity. An additional product generated with Rosaceae-derived s6pdh primers was excluded because the target identity and orthology could not be verified. The ONT run yielded 19,958 pass reads (69.27 Mb; read N50 3574 bp). Reference-enriched assembly produced a 14,824 bp candidate plastid-associated contig, approximately 9.3% of a typical Morus plastome. Its short length, incomplete and non-collinear annotations, and the absence of retained depth, polishing, assembly graph, and join support diagnostics preclude its interpretation as a complete, circular, or structurally validated plastome. This study provides a transparent pilot baseline for Mangystau mulberries and establishes quality control criteria for replicated sampling, validated markers, and deeper organelle sequencing.